@Override is a hint to the compiler, indicating that you think that you are either overriding a method from a superclass or implementing a method from an interface. If you have @Override, and there is a mistake in your method signature (wrong parameters, wrong return type, etc.), the compiler can let you know about it.

You could remove @Override from the one method where it appears in your code listing, and your code would run just fine.

Having @Override is a good idea, to help catch bugs when you are writing your app, but it is not a requirement.